The Legend of Zelda: The Wind Waker - Octorok

Octoroks are octopus-like enemies that stay underwater until Link gets close enough, where they will pop up and begin shooting projectiles at him. River Octoroks, which appear in Forest Haven and the Forbidden Woods, shoot rocks, while Sea Octoroks will shoot bombs. The River ones' shots can be bounced back with Link's shield, while the Sea ones have to be killed with the cannon.